ENZYMES

Control METABOLISM Metabolic reactions can be controlled and sped up by enzymes

metabolic reactions would be too slow to occur if no enzymes were present! End in “ase”

Properties of Enzymes Proteins Catalysts Reusable

Properties of Enzymes 4. Substrate specific 5. Sensitive to temperature 6. Sensitive to pH

Enzymes Remain Unchanged! Enzymes are not used up; Reaction ends when there is NO MORE SUBSTRATE!! Before After

Mechanism of Enzyme Action THE ACTIVE SITE is the place where the substrate binds with the enzyme substrate substrate enzyme active site

Action of Enzyme in Synthesis (TO MAKE) enzyme-substrate complex substrate Product and substrate enzyme

Action of Enzyme in Decomposition (TO BREAK DOWN) enzyme-substrate complex product substrate enzyme

Lock and Key Hypothesis Enzyme Substrate

Lock and Key Hypothesis SHAPES DON’T MATCH

Lock & Key Model ONE enzyme for every substrate Unique fit Enzyme

Enzymes are Temperature Dependent…... Most work BEST at body temperature 37oC DENATURE (change shape) at high temperatures Inactive (doesn’t work that well) at LOW temperature

What is the optimum temperature for this enzyme? How do you know?

What is pH? Used to determine the acidity or alkalinity (base) of a solution on a scale on which 7 is neutral, lower values are more acid, and higher values more alkaline (basic)

Effect of pH on Enzyme Activity -If pH of the substrate is higher or lower than optimum pH (highest enzyme activity) denaturation happens; enzyme becomes ineffective. -Different enzymes may have different optimum pH’s

What pH does pepsin work best? What pH does pancreatic lipase work?